Video stroboscopy is a medical examination procedure that combines video observation and display with a specially timed illumination to evaluate the function of the vocal cords, or larynx. During vocalization such as speech and singing, the vocal folds in the larynx vibrate too rapidly to discern the movement under constant lighting conditions. Stroboscopy solves this problem by using a strobe light to illuminate the larynx. The strobe light emits light flashes at a rate either matched with or very slightly different than the vibration base frequency of the vocal folds, causing the folds to appear to move in slow motion when viewed through the scope. An examiner may then observe the movement and function of the larynx as a patient makes particular sounds.
Such stroboscopic rhino laryngoscopy exams are typically performed with either a flexible endoscope passed through the nose. The endoscope used may also be called a stroboscopic laryngoscope, with the procedure referred to as laryngeal stroboscopy. The scope contains an optical system and a small camera for observation and recording of the exam for later review.
In existing systems, the process of laryngeal stroboscopy typically requires a global exposure type shutter arrangement for the scope camera, with the strobe light exposing the entire image sensor array at the desired position of the vocal cords during vibration. However, rolling shutter type image sensors arrays, including many CMOS image sensors, may offer higher resolution capabilities at a comparably cheaper price point to global shutter type imaging arrays. Further, the use of rolling shutter type arrays such arrays in laryngeal stroboscopy would allow interoperability of designs across existing scope platforms, reduce costs, and enhance capabilities of scopes.
What is needed, therefore, are improved systems and techniques for laryngeal stroboscopy that enable better use of rolling shutter type image sensors in scopes.